Pressure relief valve

Abstract

A pressure relief valve includes a valve body having an axial inlet port and a lateral outlet port, with an enlarged bore extending between such ports. A valve bonnet attached to the valve body slidably guides a poppet for movement between closed and open positions for closing and opening the inlet port. A seal ring positioned in the bore adjacent the inlet port sealingly surrounds the poppet in its closed position. The seal ring is axially compressed between a retainer ring and a backup surface, and a ring nut threaded in the bore compressively engages the retainer ring. The ring nut is located entirely on the inlet port side of the outlet port so it does not inhibit flow to the outlet port when the poppet is open. A poppet guide bore in the bonnet extends inwardly from a bonnet end surface, and a pair of concentric recesses of different diameters also extend into the bonnet from the end surface. One recess receives a seal ring positioned in surrounding sealing relationship with the poppet, and the other recess receives a push-in retainer for retaining the seal ring in its recess. A small diameter stem on the poppet extends into a bonnet spring receiving bore and has a rounded end received by a conical recess in a guide disc. Close fitting cylindrical locating surfaces are used for providing accurate concentricity between the bonnet and body, and between the retainer ring and the bore.

Having thus described the invention, it is now claimed: 
     
       1. A pressure relief valve comprising: a valve body having an inlet port and a lateral outlet port spaced from said inlet port, an enlarged bore between said ports, a poppet slidably guided between closed and open positions for respectively closing and opening said inlet port, biasing means for normally biasing said poppet to said closed position, a seal ring in said bore adjacent said inlet port in surrounding sealing relationship with said poppet in said closed position thereof, said seal ring being axially compressed between a retainer ring and a backup surface, an externally threaded ring nut threaded into said bore and compressively engaging said retainer ring, said ring nut being located in said bore entirely on the inlet port side of said outlet port, said valve body having stop means inwardly of said seal ring, and said stop means being engageable by said poppet in said closed position thereof.   
     
     
       2. The valve as defined in claim 1 wherein said backup surface and said stop means are on an insert received in said valve body. 
     
     
       3. The valve as defined in claim 1 wherein said poppet has a substantially flat end engaging said stop means in said closed position of said poppet, said poppet having a peripheral side wall intersecting said substantially flat poppet end at a corner area, and said seal ring engaging said peripheral side wall of said poppet closely adjacent said corner area in said closed position of said poppet. 
     
     
       4. The valve as defined in claim 1 including a bonnet threaded into said bore on the opposite side of said outlet port from said inlet port, said poppet being slidably guided in said bonnet, said bore having a larger diameter on the opposite side of said outlet port from said inlet port than on the inlet port side of said outlet port, and said bore being unthreaded along the length thereof intersected by said outlet port. 
     
     
       5. The valve as defined in claim 4 wherein said bonnet has a bonnet end surface facing toward said inlet port, a poppet guide bore extending into said bonnet from said bonnet end surface, a cylindrical first recess having a diameter substantially larger than said poppet guide bore and extending into said bonnet from said bonnet end surface coincidental with said poppet guide bore, a cylindrical second recess having a diameter substantially larger than said first recess and extending into said bonnet from said bonnet end surface coincidental with said poppet guide bore, a seal ring positioned in said first recess in surrounding sealing relationship to said poppet, and a push-in retainer secured within said second recess for retaining said seal ring in said first recess. 
     
     
       6. The valve as defined in claim 5 wherein said second recess has an axial length which is substantially less than the axial length of said first recess. 
     
     
       7. The valve as defined in claim 4 wherein said poppet biasing means comprises a coil spring and said bonnet has a spring receiving bore on the opposite side of a dividing wall from said poppet guide bore, said dividing wall having an opening therethrough and said poppet having a small diameter stem extending through said opening into said spring receiving bore, said stem having a rounded end, a guide disc having a central conical recess receiving said rounded end of said stem, and said spring being positioned between said disc and a cap positioned over the open end of said spring receiving bore. 
     
     
       8. The valve as defined in claim 7 wherein said disc has opposite faces and each said face has a said conical recess therein. 
     
     
       9. The valve as defined in claim 4 wherein said valve body bore has an open end for receiving a bonnet projection, said bonnet having an outwardly extending shoulder for cooperatively engaging a valve body end surface when said projection is fully received in said valve body bore, said bonnet having a smooth cylindrical locating surface adjacent said shoulder for close reception in a corresponding smooth internal cylindrical locating surface adjacent said valve body end surface, said valve body bore and said bonnet projection being cooperatively threaded beyond said locating surfaces, and the peak diameter of the threads on said projection being smaller than the diameter of said internal cylindrical locating surface. 
     
     
       10. The valve as defined in claim 9 including a chamfer between said end surface and said internal cylindrical locating surface for defining a seal ring receiving cavity, a seal ring positioned in said cavity and being compressed therein. 
     
     
       11. A pressure relief valve comprising: a valve body having inlet and outlet ports, a bonnet assembled to said body and slidably guiding a poppet between closed and open positions for respectively closing and opening said inlet, said body including a bore having an open end and receiving a projection on said bonnet, said bonnet having an outwardly extending shoulder cooperatively engaging an end surface on said body when said projection is fully received in said bore, said bore having a smooth internal cylindrical locating surface adjacent said open end closely receiving a smooth external cylindrical locating surface on said bonnet adjacent said shoulder, said projection and bore being cooperatively threaded beyond said locating surfaces with the peak diameter of the threads on said projection being less than the diameter of said internal cylindrical locating surface, a chamfer extending between said end surface and said internal cylindrical locating surface to define a cavity bounded by a portion of said shoulder, a portion of said external cylindrical locating surface and the surface of said chamfer, and a seal ring compressed within said cavity. 
     
     
       12. The valve as defined in claim 11 wherein said bonnet has a bonnet end surface on said projection, a poppet guide bore extending into said projection from said bonnet end surface, first and second recesses extending into said projection from said bonnet end surface coincidental with said poppet guide bore, a seal ring positioned in said first recess around said poppet, and a push-in retainer secured in said second recess for retaining said seal ring in said first recess. 
     
     
       13. A pressure relief valve comprising: a valve body having inlet and outlet ports and a threaded bore receiving a threaded projection on a bonnet, a bonnet end surface on said projection, a poppet guide bore extending into said projection from said bonnet end surface and slidably guiding a poppet between closed and open positions for respectively closing and opening said inlet port, first and second recesses extending into said projection from said bonnet end surface coincidental with said poppet guide bore, a seal ring positioned in said first recess in surrounding sealing relationship with said poppet, a push-in retainer secured in said second recess for retaining said seal ring in said first recess, a spring receiving bore on the opposite side of a dividing wall from said poppet guide bore, said poppet having a small diameter stem extending closely through an opening in said wall into said spring receiving bore and having a rounded stem end, a disc in said spring receiving bore and having opposite faces with central conical recesses therein, said stem end being received in one of said conical recesses, and a coil spring compressed between said disc and an end cap attached to said bonnet. 
     
     
       14. A pressure relief valve comprising: a valve body having an inlet port and a lateral outlet port spaced from said inlet port, an enlarged bore between said ports and having a bottom adjacent said inlet port, a poppet slidably guided between closed and open positions for respectively closing and opening said inlet port, biasing means for normally biasing said poppet to said closed position, a smooth cylindrical locating surface in said bore adjacent the bottom thereof, a small cylindrical recess in the bottom of said bore inwardly of said locating surface concentric with said outlet port, an insert closely received in said recess and shaped for cooperation with the peripheral surface of said recess to define a seal ring receiving groove in which a seal ring is received, a retainer ring closely received in said locating surface in the bottom of said bore and having an inwardly extending projection partly overlying said seal ring, means for compressing said retainer ring against the bottom of said bore with said seal ring compressed between said retainer ring projection and a lateral surface on said insert which forms the bottom of said groove, and said seal ring being in surrounding sealing relationship with said poppet in said closed position thereof. 
     
     
       15. The valve as defined in claim 14 wherein said insert has an axial projection inwardly of said seal ring which forms an inner wall of said seal ring receiving groove and also defines a stop which is engaged by said poppet in said closed position thereof. 
     
     
       16. The valve as defined in claim 15 wherein said inwardly extending projection on said retainer ring and said axial projection on said insert have opposed edges between which said seal ring engages said poppet in said closed position thereof, and said opposed edges being spaced from one another a distance substantially less than the diameter of said seal ring to thereby prevent extrusion of said seal ring between said edges under the influence of fluid pressure acting on said seal ring through said inlet port.